Small Block & Big Block Chevy Specific - About to get a free mid 80s 305 Any good to play with ?

about to get a 305 engine how much power could the 305 block handle ?

what the good and bad of this engine ? looking to turbo it

The 305 is a smog dog. It's not worth building. Factory, they topped out at about 200HP. Strip the free engine to a bare block. Set the block in the front yard. Plant flowers in each cylinder. Now go buy a 350 block and build it.

I don't know much about them, but i wouldn't waste 5 seconds on one

Id get the motor, sell it to a junk yard/high school kid, take the money, go out to lunch.

Alright, on a serious note, if it is free and you are determined to use it, the only 305s in my book worth using are the 87 up models as they are roller from the factory. So cam selection would be the same as any SBC for flat tappet, but the factory roller is the plus.

Yes, they handle boost as any other chevy motor, very well.

If you blow it up, you are not out anything, the low compression it has would work great with it i am sure. But it will lack torque, nothing soe more boost not nitrous cannot fix.

As for power, the block can handle 400 HP easily, any more than that and you need block prep work to make it live, not worth wasting money on as you can see by the above comments.

running a small positive displacement supercharger, the stock bottom end can survive 500 crank HP if you have NO detonation and keep the rpm reasonable. The most information on 305s is gonna be found hidden all over www.thirdgen.org

Forged internals, solid roller and 2 turbos.

The bad thing is the stock heads that are going to be on it are just complete junk.

Its free, take it and whore the crap out of it.

Have fun !

The reason everyone bashes this little engine is due to the bore size. At
3.736" you can't get a decent set of heads on there. The stock valves are 1.84/1.50 and that's the "high output" L69 heads. The standard 305's had 1.76/1.46. Even a set of Vortec heads would be severely shrouded and kill flow and subsequently power production. If that's what you've got and you've got money to burn.....go for it, but don't expect it to run with the big dogs! If it were me, I'd spray the ever loving crap out of it until it explodes. It's the least outlay for the most power.....and an awful lot of fun!

your in jersey. ill be up there in a few weeks on a coast guard cutter. id be more then happy to take that off your hands because i think my 92 is on its last leg. hell id even drop you a few bucks for it. im not going to BUILD it just a freshen up to hold a lil longer while i finish my 383 build for my ragtop. and plus an extra motor in the garage to me is an extra motor it can always be just a good motor on the stand "IN CASE"

Tie a rope to it and kick it off the front of the boat....its an anchor dude.


If you want to have fun with just put a 325 shot on it spray it death:D

the standard 305 valves in '76-'79 were 1.72"/1.50", thereafter they all had 1.84"/1.50". and even if you have a regular version, a set of vortec heads and a COMP XE268H10, with an RPMAirGap and a set of long-tubes will get you 370 HP at 6100 rpm. Trick Flow makes a set of heads just for 305s.

my little 305 ran good with the vortec heads on it. i used a 1094 head gasket and a 480 lift lunati cam. car weighed 3100lbs with me in it and went 8.0's all day long. stock rockers and eveything. never broke anything. i miss that. by the way whats the bore on a ls1?

my little 305 ran good with the vortec heads on it. i used a 1094 head gasket and a 480 lift lunati cam. car weighed 3100lbs with me in it and went 8.0's all day long. stock rockers and eveything. never broke anything. i miss that. by the way whats the bore on a ls1?

A little better at 3.898".

305's run for ever because the dont make enough power to break them selfes! if its free go for it, but dont expect much even with a turbo. You can build a 350 for the same price as a 305 and have a lot more power.

you can also build a 400. and make more power

Well its free I guess ill just play with it for now.

you can make some good cheap power with a 305. cubic inches are cubic inches. a 302 ford or a 302 chevy never gets knocked like a 305.

you can make some good cheap power with a 305. cubic inches are cubic inches. a 302 ford or a 302 chevy never gets knocked like a 305.

The big difference there is the bore size. The Ford 302 and Chevy 302 both have a 4 inch bore as opposed to the 305's 3.736". The small bore of the 305 causes valve shrouding killing flow into the cylinders. Can you make some power with them...yes, but for the same outlay you'll make much more with a bigger bore engine.

well the ls1's have a small bore. how do they do so well? i dont believe in the valve shrouding bs, i think there is more to the shape of the combustion chamber than anything. most people think of heads when they think of shrouding the valves. not so much bore size. ive ran that setup years ago and everyone was always impressed with the way it ran. they had to go look at the block and see the lg4 to believe it. then they looked for nitrous lines. there was none. i think its a great discussion though. alot of fun to talk about.

You're right, it is a good discussion and I'm sure we could both go on for pages, but I guess we shouldn't jack BigRich954RR's thread. :chug:

Just figured id throw out my 2 cents. Dont waste your time. 350's are dirt cheap and half the money can make twice the power. If you do go with the 305 make sure it doesnt have the swirl port heads like i know my 92 has. Cant remember the casting number on them but u cant miss the stupid fin in the intake port. Mid 80's im not sure if the swirley's were out yet.

As stated earlier the most fun you can have with it is put a 325 shot on it and see how long its lasts you. Or play that game where u mount the motor and tie the throttle open and make bets on how many minutes it runs before it explodes haha.

If it's a 305 Crossfire, scrap it. If it's a TPI forget about it!

Basically what i'm saying is, the 305 is CRAP and not worth tinkering with!

If it's a 305 Crossfire, scrap it. If it's a TPI forget about it!

Basically what i'm saying is, the 305 is CRAP and not worth tinkering with!

If your getting a TPI GIVEN to you theres no way you should forget about it! Look em up on ebay... thirdgen guys will kill for those TPI systems. Take it and throw it on a 350 and youll beat every stock LS1 off the line... thats it tho... since theyre worthless over 5k but ne way im gettin off topic here.

The consensious is 305's are junk, always have been always will be. the only things they can beat are the 307's... but thats a different thread. :eyes:

i smoked quite a few 350's with duoble hump heads with my 305. i had a vortec 350. so i took the heads off and put them on the stock 305. and ran the piss out of it. while i built the 350. believe it or not i miss that 305.

Yea lets not bash TPI there not to bad. I had a TPI 88 iroc 350 400hp and 383 about 480hp But TQ was everywhere all the time. I could lift the front wheels TPI made great TQ. I killed my street car when i went to a Carb back in high school made more power and rev alot higher. But lost all the fun of a Street car when i switch to carb. Thinking i might still have some of my old TPI parts. getting ideas now TPI 305 with a small turbo in a Jeep

a 305 with a good H/C/I can make around 340-350hp pretty easy

..a bunch of mag guys already done it..it is tru per doller u get more with a 350...but u can make a lil 305 into a beast

We actually blew up a 305 on my engine test run stand for the fun of it in the garage the other week while we drank beer and took bets on how long it would last:chug:.....damn thing ran floating the valves for a good 10 minutes before a rod kicked a hole through the block:D....they may not be powerful but the are tuff!

Look at this 305. He is running 24 lbs of boost with a vortec supercharger. He punched the 305 to a 315 and he is running 750RWHP. He shows everytime he jumps up and gets higher numbers. If you want to have fun and blow up a 305 do this.

http://www.cardomain.com/ride/2496232

Look at this 305. He is running 24 lbs of boost with a vortec supercharger. He punched the 305 to a 315 and he is running 750RWHP. He shows everytime he jumps up and gets higher numbers. If you want to have fun and blow up a 305 do this.

http://www.cardomain.com/ride/2496232

Gee whiz, all of this sounds familiar (http://www.ls1tech.com/forums/small-block-big-block-chevy-specific/1094449-305-sbc.html)...

Glad to see someone make some snot with the 305. 945ft-lbs!? On pump gas!? That's sick! Hell, he made 523hp to the wheels on the stock motor with the blower!

I've heard the 305 TPI heads are not too bad, don't have the swirl port like the TBI heads had.

I local guy I know built a 305 stroker for is 35 chevy pickup. He drove it from missouri to washington state all time time. He used a cast eagle crank, sir rods and a decent piston, I think it was like 337 cubic inches. Lots of torque. He used vortec heads with a decent hyd roller. He had a T56 behind that in his 2800 lb truck. dont' know the power but it was very respectable. Ohh yeah, and he got over 25 miles per gallon highway on that, with a 525 road demon carb.

He just pulled that out to go with a 5.3L vortec with efi and his t56,

what was the bore x stroke of the 283?

i think the whole reason people hate on the 305 is they don't know how to work on the motors passed a simple cam or other crap. trick flow now makes a set of dedicated 305 heads and i'd love to see what those could do matched with a good cam. if i didn't blow up the 305 my car came with i'd have gotten that fucker into the 12s on a 100 shot and a converter. the car was already doing low 14s with exhaust and some other mods to the motor.

i think the whole reason people hate on the 305 is they don't know how to work on the motors passed a simple cam or other crap. trick flow now makes a set of dedicated 305 heads and i'd love to see what those could do matched with a good cam. if i didn't blow up the 305 my car came with i'd have gotten that fucker into the 12s on a 100 shot and a converter. the car was already doing low 14s with exhaust and some other mods to the motor.

I think the reason people hate 305's is because if you buy a 350 for the same price and put the same money in it, it will run stupidly faster than the 305. :D Putting nitrous on it proves nothing either... sry but i could put it on a minivan and run 12's too... sorry for the flame... but after pouring money into a 305 when i was younger and didnt know better... i could have been way faster with the same money had I just got a 350...

its been discussed 8 billion times... the 350 always wins...

I think the reason people hate 305's is because if you buy a 350 for the same price and put the same money in it, it will run stupidly faster than the 305. :D Putting nitrous on it proves nothing either... sry but i could put it on a minivan and run 12's too... sorry for the flame... but after pouring money into a 305 when i was younger and didnt know better... i could have been way faster with the same money had I just got a 350...

its been discussed 8 billion times... the 350 always wins...

a 12 or 11 sec time slip is still a fast time slip no matter how you got there.:D